1. Field of the Invention
This invention relates, in general, to photocopying and, more specifically, to display and control devices for electrophotographic printers, copiers, and like devices.
2. Description of the Prior Art
Printers, copiers, and like devices or apparatus usually have some type of operator panel associated with the device. In the case of a printer remotely located from the source of the data to be printed, the panel performs the function of allowing the local operator at the printer to control certain aspects of the printer's operation and/or monitor the status of the printer's operation or condition. In such cases, the operator usually cannot make very many changes in the information printed by the printer, but may control certain printing parameters which are best observed by the local operator at the device location. These can include such parameters as activating accessory devices such as staplers, stopping the printer when a specific number of copies or output pages are produced, stopping the job if it is incorrect or if a malfunction occurs, adjusting output contrast, and restarting the printer after an empty paper supply has been replenished. Various other controls and functions are often provided.
Printer and copier devices which are designed to provide high quality, high speed, multi-mode output capabilities are, of necessity, relatively large devices. In order to convey status information and receive input instructions from the operator, hardware which is remote from the main controller board of the device is usually necessary. One of the problems with remote operator panels is the ability to communicate quickly enough with the main processor electronics section. This can be accomplished sometimes by controlling the panel over a parallel bus system or through a parallel output port. The disadvantage here is that a large number of wires is required and the susceptibility to picking up interference is sometimes a major design problem. In addition, extending the bus of a processor over a long distance to the panel requires loading, timing, and serious EMI considerations.
Although many such devices are on the market which use operator control panels, the problems of getting the information to and from a remote panel are always inherent in the design of the system. One technique used to avoid the problems of the remote panel is to make it totally self-sufficient and specifically designed for a particular class of devices. That is, let it do all of the work of processing needed to accomplish its objectives and only communicate with other devices on a limited basis. With these restrictions, the relatively small amount of communications between the panel and the main processor can be accomplished over a serial line without seriously affecting the system speed. The disadvantage is that the panel has a dedicated display and is useful for only a limited number of product configurations.
U.S. Pat. No. 4,475,806, issued on Oct. 9, 1984, discloses a copier having a display panel which is constructed in the foregoing described manner. The display panel in this patent uses a dedicated LCD display which has fixed segments which can be controlled to display certain machine or device parts or sections. Only information relating to the occurrence of a fault condition or system configuration is passed between the main processor of the copier and the processor controlling the displays on the panel. In addition, the control inputs for the copier are on another panel and are processed by the main processor rather than communicating their control requests over the communications channel between the main processor and the display panel. Although such a panel as disclosed in the referenced patent may be useful in certain applications, it does not offer the advantages provided by the universal status and control panel of the present invention.
To overcome some of the problems encountered with using status and control panels located remotely from the main device electronics, it is desirable, and an object of this invention, to provide a universal status and control panel which can quickly control and display a large variety of status information with a simple and effective interconnecting path between the devices.